You love her or you hate her, but even her most vehement non-fans would have to admit that "Roseanne" is a great series.

You love her or you hate her, but even her most vehement non-fans would have to admit that “Roseanne” is a great series.

Sitcoms are measured by their peak episodes. This season (its sixth), “Roseanne” is working harder to hit them, as the producers and writers try to balance the new chemistry of cast changes and new situations for the characters. But when the series does reach its peak, as with this episode, no show is funnier.

The seg starts slowly, with the announcement that Fred (Michael O’Keefe) is suing Roseanne’s unmarried sister Jackie (Laurie Metcalf) for custody of their yet-to-be-born baby.

But the episode, directed by Philip Charles MacKenzie and smartly written by Kevin Abbott and Stevie Ray Fromstein, picks up speed with Fred’s announcement that Roseanne’s husband Dan (John Goodman) was the inspiration for his lawsuit, which leads to the women squaring off against the men in series of verbal battles, with a funny resolution.

Some may avoid the show because of Roseanne Arnold’s persona and her off-camera activities. It’s their loss. Her Roseanne Conner is a great character , and Arnold has become a good actress; more importantly, the show over the years has maintained consistently strong writing and ensemble acting, even in the midst of on- and offscreen staff changes.

The cast, led by Arnold and Goodman, is uniformly good, with relative newcomers Glenn Quinn, Johnny Galecki and O’Keefe making solid contributions. The series’ writing is also top-notch, making strong points on such topics as blue-collar financial woes, unwed motherhood and lesbianism, while never losing its laughs.